Modification of Surface Structure by Diffusion Processes

2021 ◽  
Vol 105 (1) ◽  
pp. 371-380
Author(s):  
Jiri Prochazka ◽  
David Dobrocky ◽  
Zdenek Joska ◽  
Chien Nguyen ◽  
Jan Sedlacek ◽  
...  

In the paper an effect of a diffusion technology such as gaseous ferritic nitrocarburizing on the surface properties of selected alloyed case-hardening steel was tested. The steel 18CrNiMo7-6, primarily predetermined for carburizing and frequently utilized in manufacturing of highly strained components, where high core tensile strength as well as hard surface is demanded, was exposed to gaseous ferritic nitrocarburizing. Such treated surface was subjected to experimental methods. The microstructure observation and the determination of the white layer thickness was performed on the Opto-digital microscope Olympus DSX500i. The nitriding hardness depth of the surface layer from the microhardness profiles obtained by the microhardness tester LM247 AT LECO was deduced. The wear resistance was assessed by utilizing the Scratch test method performed on the tribometer Bruker UMT-3 TriboLab. Results of the measurements present an effect of gaseous ferritic nitrocarburizing on the surface properties of the steel 18CrNiMo7-6 and provide a perception of possibility to substitute the frequently utilized carburizing by the gaseous ferritic nitrocarburizing.

2003 ◽  
Vol 766 ◽  
Author(s):  
A. Sekiguchi ◽  
J. Koike ◽  
K. Ueoka ◽  
J. Ye ◽  
H. Okamura ◽  
...  

AbstractAdhesion strength in sputter-deposited Cu thin films on various types of barrier layers was investigated by scratch test. The barrier layers were Ta1-xNx with varied nitrogen concentration of 0, 0.2, 0.3, and 0.5. Microstructure observation by TEM indicated that each layer consists of mixed phases of β;-Ta, bcc-TaN0.1, hexagonal-TaN, and fcc-TaN, depending on the nitrogen concentration. A sulfur- containing amorphous phase was also present discontinuously at the Cu/barrier interfaces in all samples. Scratch test showed that delamination occurred at the Cu/barrier interface and that the overall adhesion strength increased with increasing the nitrogen concentration. A good correlation was found between the measured adhesion strength and the composing phases in the barrier layer.


Alloy Digest ◽  
1959 ◽  
Vol 8 (2) ◽  

Abstract AISI 4320 is a nickel-chromium-molybdenum case hardening steel having high toughness and shock resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-80. Producer or source: Alloy steel mills and foundries.


Alloy Digest ◽  
1965 ◽  
Vol 14 (7) ◽  

Abstract AISI 8615 is a low-carbon, nickel-chromium-molybdenum alloy steel capable of producing high core strength and toughness. It is a case hardening steel recommended for heavy duty gears, cams, shafts, chains, fasteners, piston pins, etc. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, machining, and joining. Filing Code: SA-180. Producer or source: Alloy steel mills and foundries.


Alloy Digest ◽  
1960 ◽  
Vol 9 (4) ◽  

Abstract AISI 3120 is a low-carbon, chromium-nickel case-hardening steel offering good toughness and shock resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: SA-97. Producer or source: Alloy steel mills and foundries.


2021 ◽  
Vol 15 (2) ◽  
pp. 137-150
Author(s):  
Susanne Elisabeth Thürer ◽  
Anna Chugreeva ◽  
Norman Heimes ◽  
Johanna Uhe ◽  
Bernd-Arno Behrens ◽  
...  

AbstractThe current study presents a novel Tailored Forming process chain developed for the production of hybrid bearing bushings. In a first step, semi-finished products in the form of locally reinforced hollow profiles were produced using a new co-extrusion process. For this purpose, a modular tool concept was developed in which a steel tube made of a case-hardening steel, either C15 (AISI 1015) or 20MnCr5 (AISI 5120), is fed laterally into the tool. Inside the welding chamber, the steel tube is joined with the extruded aluminum alloy EN AW-6082. In the second step, sections from the compound profiles were formed into hybrid bearing bushings by die forging. In order to set the required forming temperatures for each material—aluminum and steel—simultaneously, a tailored heating strategy was developed, which enabled successful die forging of the hybrid workpiece to the desired bearing bushing geometry. Using either of the case-hardening steels in combination with aluminum, this novel process chain made it possible to produce intact hybrid bearing bushings, which showed both macroscopically and microscopically intimate material contact inside the compound zone.


Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 896
Author(s):  
Matthias Schmitt ◽  
Albin Gottwalt ◽  
Jakob Winkler ◽  
Thomas Tobie ◽  
Georg Schlick ◽  
...  

The carbon content of steel affects many of its essential properties, e.g., hardness and mechanical strength. In the powder bed fusion process of metals using a laser beam (PBF-LB/M), usually, pre-alloyed metal powder is solidified layer-by-layer using a laser beam to create parts. A reduction of the carbon content in steels is observed during this process. This study examines adding carbon particles to the metal powder and in situ alloying in the PBF-LB/M process as a countermeasure. Suitable carbon particles are selected and their effect on the particle size distribution and homogeneity of the mixtures is analysed. The workability in PBF-LB is then shown. This is followed by an evaluation of the resulting mechanical properties (hardness and mechanical strength) and microstructure in the as-built state and the state after heat treatment. Furthermore, potential use cases like multi-material or functionally graded parts are discussed.


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